1. Field of the Invention
The invention is relative to a hydrodynamic-mechanical multispeed compound transmission with at least four speeds for use in vehicles, especially in busses, and also to a method of developing a transmission line from a basic transmission in the form of a hydrodynamic-mechanical multispeed compound transmission with at least four theoretically possible gear steps for use in vehicles for differing requirements.
2. Description of the Related Art
Hydrodynamic-mechanical compound transmissions comprising a hydrodynamic speed-torque converter and a mechanical transmission part are known in many embodiments. Publication DE 36 04 393 C2 discloses a hydrodynamic compound transmission comprising a torque converter and a gearbox connected together in series. The gearbox comprises two planetary gear trains. The planet carriers of the two planetary gear trains are coupled to each other and form the output of the gearbox. The number of required planet gear webs or planetary gear trains can be kept low with such an arrangement and the transmission can therefore be built short and three gear steps can be realized given the appropriate assignment of shifting devices. The hydrodynamic speed-torque converter comprises an impeller, a turbine gear and two stators or reactorsxe2x80x94a first stator and a second stator. Means are provided that make possible a coupling of the turbine gear as well as of the first stator to the mechanical transmission part in the form of the gearbox. Specifically, the entire transmission input shaft can be coupled either via the hydrodynamic speed-torque converter and thereby via the turbine gear to the sun gear of the one planetary gear train of the mechanical transmission part or directly via a so-called bridge coupling to the latter. The first stator is connected via a freewheel to the sun gear of the second planetary gear train of the mechanical transmission part. The characteristic properties of the speed-torque converter in each range of the translation ratio and the translation ratio of the mechanical transmission part are changed by shifting the transmission path of the moment emanating from the first stator shaft, namely, by the selective actuation of the coupling- and/or braking devices that either make possible a fixing of the first stator shaft or a coupling of the first stator shaft to the turbine gear shaft and therewith of the first sun gear of the first planetary gear train. The advantage of the three-speed transmission described in this publication consists unambiguously in its small size and its low weight. However, an appropriate design of this existing transmission as regards the main instance of use or an expensive modification of the same is necessary for optimizing certain parameters, e.g., the fuel consumption of a vehicle or for making possible higher final design speeds of the vehicle.
The invention solves the problem of further developing a hydrodynamic-mechanical compound transmission of the initially cited type in such a manner that it can meet the existing requirements of use in an even more optimal manner retaining the advantages of the low weight and the small size. Depending on the intended use (e.g., for the use in busses for city traffic (use with low final design speeds) or primarily for overland traffic (use with high final design speeds), the following should be striven for: An optimal, that is, as hyperbola-shaped as possible, graph of tractive force, low fuel consumption and a selective useable speed number (4- or 5- or 6-speed transmission), depending on the final design speed) as well as an overdrive that is simple to realize for the last-named possibility of use. The transmission should be able to be universally used, that is, e.g., for busses with a low weight and a rather large weight (bandwidth weight mmin-mmax) as well as with different final design speeds (bandwidth final design speed vmin-vmax) without significant additional modification of transmission components and should make possible different areas of application and therewith different modes of operation, especially the starting variants.
The hydrodynamic-mechanical multispeed compound transmission with a hydrodynamic transmission part and a mechanical transmission part, have hydrodynamic transmission part and mechanical transmission part connected in series, viewed in the direction of the power flow, with at least means being provided for circumventing the hydrodynamic transmission part during the transmission of power, are designed in accordance with the invention as regards the mechanical transmission part in such a manner regarding the translations that at least one gear step jump or progression phi is achieved between two speeds adjacent to one another between 1.1 and 1.45. The hydrodynamic transmission part comprises at least one hydrodynamic speed-torque converter. The mechanical transmission part comprises a mechanical speed-torque conversion device with at least two planetary gear trains. The hydrodynamic-mechanical multispeed compound transmission is preferably equipped with a rear-mounted train (i.e., after-shifting- or secondary switching set) so that theoretically 6 gear steps are conceivable. It is particular advantageous in this case to design the mechanical transmission part in such a manner that the following gear step jumps phi are achieved:
phixe2x89xa61.45 between the first and the second gear step and the second and the third gear step;
phixe2x89xa61.35 between two successive gear steps of the following speeds.
Phi can remain constant thereby or can be designed to fall in the direction of higher speeds.
The design of the transmission in accordance with the invention makes it possible to attain as hyperbola-shaped as possible graph of tractive force in the tractive force/speed diagram even at low speeds. Moreover, different operating concepts with an optimal result as concerns different design speeds can be realized by an appropriate control of the individual transmission elements on account of this basic speed graduation. For example, when the transmissions are used in busses both the lower speed range, that is particularly significant for city buses, and the upper speed range, that constitutes the main range of use in travel buses, are considered thereby. Therefore, the gear step jumps in the upper speeds that is, from an initial speed into the next higher speed, are preferably designed to be constant, which corresponds to the customary design criteria in the upper speeds, especially in the case of transmissions for use in travel buses. In the case of lower design speeds (greater axial translations), the first speed (speed with the greatest translation), can remain uncontrolled as a result. The speed jump between converter speed and 2nd speed remains below 1.8 therewith.
The mechanical transmission part is preferably designed in such a manner that the transmission elements in the first gear step that participate in the speed-torque conversion realize a translation in a range of 3 less than i less than 3.25 and in the last gear step a translation in a range of 0.7 less than i less than 0.9.
A plurality of control or drive variants can be realized on this basis with a basic transmission component without additional modification, which variants form the basis for the development of a series from a single basic transmission in the form of a hydrodynamic-mechanical multispeed compound transmission with at least four theoretically possible gear steps for use in vehicles for different requirements.
Specifically, the following can be achieved retaining the same basic transmission design by variation of the control of the transmission elements:
a) A plurality of transmission- and speed variants (4/5/6-speed),
b) A plurality of starting variants,
c) A plurality of drive variants by mixing the individual transmissions or speed variants with the individual start variants.
The individual speed variants are realized by omitting gear steps. The basic transmission concept is designed in such a manner that a plurality of gear steps, especially a maximum of 6 gear steps can be theoretically realized. The speed graduations in accordance with the invention are valid thereby for the design of the mechanical transmission part for a 6-speed transmission variant. The individual transmission variants are realized by omitting individual speeds. However, due to the association of the speeds with the individual mechanical gear steps, no change in the gear step jumps takes place thereby between the gear steps theoretically possible for the initial basic transmission. This means that gear steps can be omitted in such a manner from the sequence of individual gear and shifting steps possible for the basic transmission that can be theoretically inserted or used and that are characterized by the actuation and the uncoupling of the individual shifting devices for the individual speeds that, e.g., when the speed that is the first speed in the possible sequence of the shifting steps for the basic transmission is omitted, the first speed that is used corresponds to the second speed in the sequence of shifting steps theoretically set for the basic transmission. When gear steps are omitted, as a rule only the corresponding actuation for the speed change is eliminated.
The systematic elimination of the gear step that is always the greatest takes place thereby in such a manner that no intermediary gear steps are removed from the frequently used drive range but rather, depending upon the requirements of use, either the first speed, the last speed or a speed following or preceding it are removed. Achieving the elimination of gear steps by eliminating the rear-mounted train is consciously thereby avoided. Transmission variants with six speeds, a transmission variant with five speeds, and a transmission variant with four speeds can be realized in a multispeed compound transmission with six speeds. The individual transmission- and speed variants can either be basically offered from the beginning as a permanent transmission-or speed variant or can be freely selected and replaced when inserted in vehicles. Thus, in the first instance cited, the selection can be made by a customer already at the time of ordering the transmission, in which case this selection is then set for the further purposes of use. In the second instance the change of the speed variant permits a shifting of the area of application. Especially, when used in busses or in construction vehicles, for which different areas of application are requiredxe2x80x94in the case of buses their use in cities, overland travel and their use as travel buses and in the case of construction vehicles group operation as well as street operationxe2x80x94the possibility of making a free selection offers significant advantages as regards the driving behavior in the particular main area of application. Thus, it is conceivable, for example, to omit the first and sixth speed gear in a correspondingly designed multispeed compound transmission with six speeds in city traffic, which means starting in the second speed with no phi shift taking place due to the omission of the individual speeds. This means, in particular, that in the second speed, which is now used for starting, the mechanical transmission part is designed in such a manner that it experiences a gear step jump from the speed that is now the first of a magnitude of the one that takes place in the theoretically designed six-speed basic transmission between the first and the second speed. It should be considered for overland buses whether the first speed should be omitted from the transmission theoretically designed for six speeds as a result of which the second speed is used for starting and in particular the higher speed range, that represents a main area of application for overland buses, is used.
Based on the transmission design with the gear steps in accordance with the invention, different starting concepts with different goals, e.g., high available power or low fuel consumption, can be realized in a simple manner by different control variants of the individual transmission elements, in particular of the individual transmission elements for the individual gear steps and of the selection of the transmission of power by a hydrodynamic transmission part or by circumventing the hydrodynamic transmission part. Moreover, it is possible to cover a broad range of use with only one transmission.
The integration of a rear-mounted train, that is a component of the mechanical transmission part, in the basic transmission component consisting of a mechanical transmission part and a hydrodynamic transmission part makes multiple speeds possible, which for its part has the result that the operating area to be covered can be realized with a plurality of speeds, and preferably at least one overdrive or a so-called overdrive speed is provided. An optimal adaptation to the operation in the optimal fuel consumption range of the driving machine can be realized by means of the higher transmission spread total phi.
Based on the basic transmission component consisting of a mechanical transmission part and a hydrodynamic transmission part with a rear-mounted train and theoretically more than four speeds, a plurality of starting variants can be realized that make possible:
a) A thrifty drive behavior as regards consumption, or
b) An especially comfortable or, e.g., an especially performance-oriented drive behavior, or
c) A mixed form of all of the latter.
Even the starting variants can be stored as selectable variants in a transmission control and a control of the individual transmission elements takes place in accordance with the selection of the desired starting behavior.
A mechanical speed-torque converter is preferably used that comprises at least two planetary gear trains. A connection adapted to rotate in unison exists between a first element of the first planetary gear train and a second element of the second planetary gear train which connection simultaneously forms the input for the rear-mounted train. Their planet carriers are preferably coupled to each other and form the output of the mechanical speed-torque converter, which brings about a savings of space.
The hydrodynamic speed-torque converter preferably comprises two stator devices. A first stator is coupled thereby to the first planetary gear train of the mechanical speed-torque converter. A second stator of the hydrodynamic speed-torque converter is coupled via a freewheel to the transmission housing. The torques to be supported can be used to elevate the tractive force.
An example of an advantageous transmission design with the parameters of the invention is designed in detail as follows: the hydrodynamic transmission element comprises at least one impeller, one turbine gear and a stator device comprising a first stator and a second stator. The second stator is connected via a freewheel to the transmission housing. The first stator has a driving connection via a so-called stator shaft to the mechanical speed-torque converter. The mechanical speed-torque converter comprises at least two planetary gear trains, a first planetary gear train and a second planetary gear train. Each planetary gear train comprises a sun gear, a internal-geared wheel, planet gears and a planet carrier. The two planetary gear trainsxe2x80x94the first planetary gear train and the second planetary gear trainxe2x80x94are coupled together in such a manner that they rotate in unison. The first transmission element of the first planetary gear train, which is connected to a first transmission element of the second planetary gear train in such a manner that it rotates in unison with it, is preferably formed by the planet carrier of the associated planetary gear train. The two sun gears of the individual planetary gear trains, of the first planetary gear train and of the second planetary gear train, form the inputs of the mechanical speed-torque converter. The first input, that is coupled to the sun gear of the first planetary gear train, is connected via flywheel to the first stator of the hydrodynamic speed-torque converter. The sun gear of the second planetary gear train is preferably connected to the turbine gear shaft, that can be coupled either via the hydrodynamic speed-torque converter or the bridge coupling to the transmission input shaft. The hydrodynamic speed-torque converter is arranged in the transmission in such a manner that its turbine impeller can be fixed on the transmission housing whereas the rotor impeller is preferably coupled to the output of the mechanical speed-torque converter. This output is formed by the transmission elements, that are coupled to each other, of the two planetary gear trains, preferably in the present case of the coupling of the planet carriers. The output of the mechanical speed-torque converter forms the input of the mechanical rear-mounted step and is therewith coupled via the corresponding speed graduation to the transmission output shaft. The hydrodynamic retarder thus becomes active on the transmission output shaft via the rear-mounted step and exercises therewith the function of a secondary retarder. In addition, the rotor impeller of the hydrodynamic retarder experiences a translation by the rear-mounted step. The hydrodynamic retarder can be operated, relative to the speed of the output shaft, with two different translations over the entire operating range. In order to achieve the same braking moments, independently of the speed, the filling of the retarder must be greater when the rear-mounted group is translated into rapid speed then in the xe2x80x9cdirect translationxe2x80x9d case. Depending on the shifting-back strategy, the filling must be adapted if all speeds are successively shifted back. The filling must not be adapted if a shifting back takes place only at every second speed. The coupling of the hydrodynamic retarder to the output shaft that takes place in this manner makes it possible to always realize optimal braking procedures and achieve an optimal braking behavior.
In order to realize the individual gear steps, shifting devices in the form of braking devices and coupling devices are provided that are preferably designed with a laminar construction. The individual shifting devices are to be actuated in accordance with the desired speed to be used and the translation obtainable thereby. To this end a transmission control is preferably provided. A first braking device serves to brake the stator shaft and therewith the sun gear of the first planetary gear train. A second braking device serves to brake the internal-geared wheel of the first planetary gear train and a third braking device to brake the internal-geared wheel of the second planetary gear train of the mechanical speed-torque converter. A further, fourth braking device serves to brake the sun gear of the rear-mounted step. A first coupling element serves to realize the connection, adapted to rotate in unison, of the sun gear of the first planetary gear train and of the sun gear of the second planetary gear train. The control of the individual shifting devices makes possible different gear steps and, in combination with the selection of the transfer of power via the hydrodynamic transmission part or under circumvention of the hydrodynamic transmission part, different modes of operation, especially starting programs. In the preferred embodiment, the second element of the first planetary gear train can be braked by a first braking device, a third element of the first planetary gear train by means of a second braking device and a third transmission element of the second planetary gear train by means of a third braking device. The shifting elements designed as braking devices and/or coupling devices are preferably designed with a laminar construction.
The rear-mounted train comprises at least one planetary gear train comprising a sun gear, a internal-geared wheel, planet gears and a planet carrier. The input of the planetary gear train is formed thereby by the planet carrier of the planetary gear train and the output by the internal-geared wheel of the planetary gear train. The planetary gear train is associated with a further, fourth braking device and a further, second coupling device, the fourth braking device can be coupled to the sun gear of the planetary gear train. The second coupling device serves to couple the sun gear to the planet carrier of the planetary gear train.
The rear-mounted step serves in the present instance to split the three shifting stages that can be realized with the basic transmission into two partial stages. This means that the individual, successive speeds can be realized with actuation of the same shifting elements in the basic transmission, that is, the mechanical speed-torque converter, by alternately actuating the appropriate shifting devices, coupling- and/or braking devices in the rear-mounted step. Two successive speeds, viewed from the first speed, are thus distinguished substantially by actuating the same shifting devices in the basic transmission. The transfer of power can take place thereby via the hydrodynamic transmission part or while circumventing it, as desired. As a rule, the mechanical drive-through is shifted in speeds 3, 4, 5 and 6 with circumvention of the hydrodynamic speed-torque converter. In speeds 1 and 2 the transmission of power takes place via the converter too. According to the invention the designing of the mechanical transmission part takes place in such a manner that gear step jumps are realized in the individual 6 speeds of
phixe2x89xa61.45 between the first and the second speed and between the second and the third speed and
phixe2x89xa61.35 between two successive gear steps of the following speeds with the latter, i.e., the mechanical transmission part, without taking the hydrodynamic speed-torque converter into consideration.
In the rear-mounted step of the preferred embodiment the fourth braking device and the second coupling device are actuated alternately in successive speeds. Specifically, the following shifting devices are actuated in the individual speeds whereas the remaining shifting devices are uncoupled, i.e., released:
1st speed: Second coupling device and third braking device
2nd speed: Third and fourth braking device
3rd speed: Second coupling device and first braking device
4th speed: First and third braking device
5th speed: First and second coupling device
6th speed: First coupling device and fourth braking device.
The following starting variants result in detail for the preferred embodiment of the hydrodynamic-mechanical compound transmission, which starting variants differ essentially by the number of shifting operations and their influence on the operating range of the drive machine. The different starting variants result from the realization of the transmission of power via the speed-torque converter or with circumvention of the speed-torque converter in the individual gear steps. The individual gear step is determined thereby by actuating the switching devices on the mechanical speed-torque converter without taking the rear-mounted train into consideration. The shifting elements of the rear-mounted train are actuated in such a manner for realizing variants that the particular gear translation is set.
Only possible starting variants are described in the flowing, taking no consideration of the shifting of all further speeds. The subsequent speed can be shifted in the same manner.
Transmission of power via the hydrodynamic speed-torque converter in the first speed onto the mechanical speed-torque converter (that is, actuation of shifting elements as in the first gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the greater translation is set).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic transmission part, especially of the hydrodynamic speed-torque converter, onto the mechanical speed-torque converter upon actuation of the shifting elements in the first gear by putting in operation the converter bridge coupling and the through coupling.
Transmission of power via the hydrodynamic speed-torque converter in the second gear, that is, actuation of the shifting elements around the mechanical speed-torque converter as in the second gear and uncoupling of the through coupling.
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the second gear and, e.g., actuation of the converter bridge coupling.
Transfer of power from the transmission input shaft under circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
Transfer of power via the hydrodynamic speed-torque converter in the first gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the first gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the greater translation is set).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic transmission part, especially of the hydrodynamic speed-torque converter, onto the mechanical speed-torque converter upon actuation of the shifting elements in the first gear and the lock-up coupling.
Transmission of power from the transmission input shaft under circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the second gear.
Transmission of power from the transmission input shaft under circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
All other higher speeds can be shifted in the same manner.
Transmission of power via the hydrodynamic speed-torque converter in the first gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the first gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the greater translation is set).
Transfer of power via the hydrodynamic speed-torque converter in the second gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the second gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the smaller translation is set).
Transmission of power from the transmission input shaft under circumvention of the hydrodynamic transmission part, especially of the hydrodynamic speed-torque converter, onto the mechanical speed-torque converter upon actuation of the shifting elements in the second gear (rear-mounted train small translation).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
Transmission of power via the hydrodynamic speed-torque converter in the first gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the first gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the greater translation is set).
Transmission of power via the hydrodynamic speed-torque converter in the second gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the second gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the smaller translation is set).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
Transmission of power via the hydrodynamic speed-torque converter in the first gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the first gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the greater translation is set).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the second gear.
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
Transmission of power via the hydrodynamic speed-torque converter in the second gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the second gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the smaller translation is set).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic transmission part, especially of the hydrodynamic speed-torque converter, onto the mechanical speed-torque converter upon actuation of the shifting elements in the first gear.
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic transmission part, especially of the hydrodynamic speed-torque converter, onto the mechanical speed-torque converter upon actuation of the shifting elements in the second gear.
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
Transmission of power via the hydrodynamic speed-torque converter in the second gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the second gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the smaller translation is set).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic transmission part, especially of the hydrodynamic speed-torque converter, onto the mechanical speed-torque converter upon actuation of the shifting elements in the second gear.
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
Transmission of power via the hydrodynamic speed-torque converter in the second gear onto the mechanical speed-torque converter (that is, actuation of the shifting elements as in the second gear, with the shifting elements of the rear-mounted train actuated in such a manner that only the smaller translation is set).
Transmission of power from the transmission input shaft with circumvention of the hydrodynamic speed-torque converter upon actuation of the shifting elements in the third gear.
Variants 1,2,5 and 6 represent economical programs whereas variants 3,4,5 and 8 make possible a comfortable mode of operation. The starting variants are to be selected in accordance with the desired effect. The conversion in accordance with the apparatuses takes place as a rule via a transmission control device or regulating device that can be integrated in the central drive control of the vehicle or is at least coupled to it and in this manner an optimal engine-transmission management can be realized in accordance with the requirements of use under very varied borderline conditions.
Based on this six-speed design, the possibility of selecting different transmission variants can also be made available in accordance with the requirement of use. These variants can be firmly predefined upon ordering, as already mentioned above, or can be made available in a freely selectable manner. There is the possibility in the present instance of converting the multispeed compound transmission with the theoretically six possible gear steps into a multispeed compound transmission with four or five gear steps without having to change anything in the design of the transmission. The transmission unit can be realized in accordance with the advantageous design described and the individual transmission variants are realized solely by controlling the individual transmission elements and changing the course of the progression and the sequence of the control of the transmission elements. In particular, individual gear graduations are eliminated. However, the elimination does not take place in the main areas of use, that is, no middle gear steps or speeds are removed but rather the smallest or the largest gear steps are preferably eliminated. Solely the actuations in these gear stages to be eliminated are no longer performed thereby in accordance with the shifting [switching] plan so that the latter remain associated with the theoretically six possible speeds as regards the actuation of the individual shifting devices and thus the gear graduations do not depend on the shifted gear steps but rather on the original six theoretical or selected gear steps. If, for example, the theoretical first and the sixth speed are eliminated for the use of the transmission in a city bus, the bus will start in the theoretical second speed and the gear graduation between the starting procedure and the next-following procedure corresponds to the gear graduation of the theoretical speed or gear, that is, of the transition from the second into the third speed.
The possibility of selecting the transmission variants (4-, 5-, 6-speed transmission) is preferably offered under the aspect of universality in combination with the possibility of selecting the starting variants (economical drive mode, comfortable drive mode, performance-oriented drive mode). As concerns the devices, the transmission unit can be associated with a control device that is either a component of the transmission unit, and is therefore directly associated with the latter, or that can be integrated in a central drive control. A further conceivable possibility is to place these individual possibilities in the control device associated with the transmission in which instance, as regards the modification concerning the cooperation with different drive machines, the individual starting variants and transmission variants can be fixed by means of appropriate performance characteristics or mapping for the individual possible drive machines and requirements of use and when incorporated into a vehicle, the drive control takes this data directly from the transmission.
However, a possibility of selecting the actuation of the individual shifting devices as regards the sequence and the progression is preferably always provided in order to expand therewith the spectrum of use of the vehicle in which this transmission is built. The concrete constructive and component conversion is in the area of activity of a competent expert, given knowledge of this basic concept of the invention.
The design of the invention is explained below with reference made to the figures.